ANSWERS TO INNOVATORS QUIZ

Den Kamen, right, rides his iBot alongside Michelin's Tweel at an auto show in Detroit last year. Kamen designed the iBot to help wheelchair-bound people navigate stairs and communicate with standing people at eye level.
(By Jeffrey Sauger -- Bloombergnews)

In a sense, the questions on Page D1 are trick questions. The way technology develops makes it hard to give credit to a single person for innovations that may build on the work of many who came before. Also, techies love to fight over fine points. Following are explanations of how some of these people came to be especially associated with particular advances:

1. Many deserve credit for creating what we know today as the personal computer. Steve Jobs co-founded Apple Computer and helped popularize the spread of the PC, as well as innovations such as the mouse and the graphical interface. Bill Gates co-founded Microsoft and went on to spread PC mania around the globe, along with the Windows operating system. John Hodgman is the comedian who plays "PC" in the new Apple ads.

2. Vinton G. Cerf and Robert Kahn get credit for devising the protocols, or the data-transmission system, that let computers talk to one another and makes the Internet possible. Former vice president Al Gore gets a lot of flak for supposedly claiming to have "invented" the Internet; actually, he said he took initiative in creating the Internet, and in fact he did introduce legislation in Congress that helped spur its creation.

3. Bill Gates wishes he created the iPod. Jobs, of course, oversaw its birth at Apple Computer, and the device's elegant design -- along with the ease of using the iTunes Web site -- helped it quickly take over the market. The iPod was in no way the first digital music player, though. Rob Glaser -- a former Microsoft employee -- created earlier digital music management systems at RealNetworks.

4. Martin Cooper worked at Motorola in the 1970s when he devised the cellular phone concept, a method for relaying calls from tower to tower. Arthur C. Clarke is the science-fiction writer credited with coming up with a vaguely similar idea: the communications satellite. Cher Horowitz is the character Alicia Silverstone played in the movie "Clueless," which featured lots of rich kids talking on bulky cellphones.

5. Ian Wilmut and Keith Campbell were leaders of the British team that created Dolly the sheep in 1997, the first case of a mammal cloned from an adult cell. James D. Watson and Francis Crick won a Nobel Prize in 1962 for figuring out the structure of DNA. Steven Spielberg directed "Jurassic Park," in which cloned dinosaurs terrorized Laura Dern.